Isotopes are atoms of an element with the same number of protons but different numbers of neutrons. Some of these isotopes are stable and exist fine with the extra neutrons. Others, however, are unstable, making these atoms radioactive. These are called radioisotopes and are useful in a variety of sciences, including biology, mining, industry and agriculture.

Carbon 14 dating

Carbon 14 is a radioactive isotope of carbon. Carbon normally has 12 neutrons, but isotopes with 13 and 14 neutrons also exists. Carbon with 14 neutrons is radioactive, decaying into nitrogen 14, but with a very long half-life (over 5,000 years). Therefore, in materials that were once alive, the amount of carbon 14 will steadily decrease over time. Calculating backwards, scientists can measure the amount of carbon 14 in a dead organism (say, a mammoth bone or wood from an ancient tree) and determine when the organism died, up to about 60,000 years ago.

Radioisotopes Used in Diagnostic Imaging (Tracers)

Radioisotopes can be used as tracers within a living organism to trace what is going on inside the organism at an atomic level; that is, radioisotopes can be injected or ingested by the organism, and researchers can trace the internal activities using the radioactivity. Medical specialists can use radioisotopes to see internal processes and conditions inside the human body. Gallium-67, for instance, can be ingested by patients. When the patient undergoes an MRI or PET scan, doctors can trace the substance inside the body and see what’s going on without invasive surgery. Other radioisotopes, such as Iodine-123 and Iodine-125, help doctors diagnose thyroid disorders and metabolic disorders in a similar way.

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Radioisotopes Used in Medical Treatments

Radiation in radioisotopes is useful in treating certain types of illnesses, particularly cancerous tumors. Cesuim-137 and Cobalt-60 are both used to shrink the size of tumors within the bodies of cancer patients. Cobalt-60 is also used to sterilize medical instruments. Some radioisotopes are used to diagnose and treat other disorders, such as Chromium-51, which helps doctors determine the survival rate of red blood cells.

Radioisotopes Used in Agriculture

Agriculturists can find out how effectively a plant uses a fertilizer by using certain radioisotopes. Phosphorus-32 is also used in molecular biology studies and genetics research. Sometimes, particular radioisotopes are used to cause a specific genetic mutation in plants to breed certain traits into or out of the plant. Some agriculturists are also able to use radioisotopes to cause genetic mutations in plants to make them less susceptible to attacks by pests.

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About the Author

Suzy Kerr graduated from Grady School of Journalism and Mass Communications at the University of Georgia. She completed her Master's degree in Nutrition Sciences, also at the University of Georgia. Suzy has been a successful health, fitness and nutrition writer for more than 10 years, and has been published in various print and online publications.